This invention relates to a pattern reading device to be used as an input unit for e.g. an electronic computer.
In an electronic computer which processes a wide variety of massive slips (hereinafter referred to as cards) efficiently and automatically, there is required an input unit which converts figures and/or letters in the cards into electric signals for input. For the input units, there are generally used card readers or tape readers which punch cards or paper tapes by means of keypunches and convert them into electric signals, and optical pattern reading devices which convert the figures and/or letters in the cards into electric signals by using light and perform interpretation by means of discrimination circuits.
The aforesaid card readers or tape readers are disadvantageous because they would require experts such as keypunches as well as prolonged input time, whereas the optical pattern reading devices are easy to operate and require only short process time, thereby enjoying a wide range of use.
Since such pattern reading device is so designed that an optical reader reciprocates to read patterns such as letters and figures entered in each line on the cards, such cards should be carried smoothly at precisely fixed pitches for confrontation with the reader without skewing the cards. Therefore, in the prior art, there has been used a means for conveying each fed card sucked by a vacuum rotary drum. However, such means may not prevent the above-mentioned skewing completely, and it is hard to secure conveyance of the cards at accurate pitches with such means. Further, thus increased size of the mechanism would not only require larger space but lead to louder noises at operation and higher cost.